Tobacco smoke filters

ABSTRACT

A tobacco smoke filter filled with a smoke permeable composition capable of reducing the toxic effect of tobacco smoke on alveolar (lung) macrophages, comprising N,N&#39;&#39;-diphenyl-p-phenylenediamine (DPPD) which may be mixed with flutathione, active charcoal or mixed with or impregnated into known filter material such as cellulose acetate.

United States Patent Diluzio [151 3,658,070 [4:] Apr. 25, 1972 [54] TOBACCO SMOKE FILTERS [72] Inventor: Nicholas R. Diluzlo, 732 Fairfield Avenue,

Gretna, La. 70053 [22] Filed: Oct. 1, 1970 [21] App1.No.: 77,247

[52] U.S.Cl ..131/267, 131/107, 131/109, 131/265 [51] Int. Cl ..A24b 15/02, A24d 01/06 [58] Field of Search 131/10 R, 266, 267, 269, 262 A, 131/261 [56] References Cited UNITED STATES PATENTS 1,842,266 1/1932 Hicks... ..131/17 R 2,152,602 3/1939 Ott ...13l/17RX 2,513,002 6/1950 Chenicek ...l3l/17 R X 2,968,306 ..131/266 1/1961 Tovey et a1,

Primary Examiner-Samuel Koran Assistant Examiner-G. M. Yahwak Attorney-label, Baker, York and Jones [57] ABSTRACT A tobacco smoke filter filled with a smoke permeable composition capable of reducing the toxic effect of tobacco smoke on alveolar (lung) macrophages, comprising N,N'-diphen \'l-pphenylenediamine (DPPD) which may be mixed with flutathione, active charcoal or mixed with or impregnated into known filter material such as cellulose acetate.

6 Claims, 3 Drawing Figures PATENTEDAPR 2 5 m2 INVENTOR NICHOLAS R. D! LUZ/O yw'vs TOBACCO SMOKE FILTERS The present invention relates to tobacco smoke filters which are suitable for employment in cigarettes, pipes, cigarette holders or cigar holders.

The present filter, classified as a chemical filter, has profound advantages over other filters knownto the art by being able to modify the toxic and/or lethal effects of cigarette smoke extracts on alveolar macrophages, the primary host defense cell ofthe lung.

.The filters currently available are essentially employed to remove particulate and solid components of smoke as well as to dilute the gaseous components of smoke with air. The gaseous phase of the smoke readily passes through such filters resulting in irritation to the lung tissue and, as will'be noted later, profound lethality to isolated alveolar macrophages, a cell whose primary function is to maintain a proper lung environment by detoxification and destroying a variety of agents.

The gases derived from burning tobacco smoke contain highly reactive, low molecular weight, volatile components, of which acetaldehyde is characteristic, as well as free radicals and large quantities of gaseous ions induced by the high temperatures, which can approach l,000 C resulting in pyrolization and distillation.

In addition, free radicals which have been demonstrated to be cytotoxic have also been demonstrated to occur in the gaseous phase of smoke. The chemical filtering material incorporated in the present invention has the ability, in the classical role of antioxidants as free radical stoppers, to lower the cytotoxic substances of cigarette smoke, possibly by reducing the attack of free radicals or other such reactive agents on pulmonary alveolar cells and therefore maintaining cell viability. Since free radicals have been implicated in the genesis of neoplasia, a beneficial effect of the antioxidant filler may be implied. In addition, the chemical filter has the ability to prevent smoke-induced decreases in circulating plasma lipid antioxidants.

' It is the object of the present invention to provide a filter which, I have discovered, reduces the disclosed toxicity of cigarette smoke on alveolar macrophages.

l have discovered that the above object can be accomplished by having a tobacco smoke filter such as a cylindrical container filled with a smoke permeable composition comprising the lipid soluble antioxidant N,N'-diphenyl-p-phenylenediamine (DPPD), preferably mixed with the water soluble antioxidant glutathione. The DPPD or the DPPD mixed with glutathione may be used alone or mixed with other ingredients such as with activated charcoal or impregnated into a filter carrier material such as cellulose acetate, paper, wood pulp, cotton, fibrous polyolefins, cellulose esters in fibrous or plastic form, regenerated cellulose, silica gel, alumina, tobacco and the like. Likewise the DPPD may be mixed with other chemical filters such as the amide filter of U.S. Pat. No. 3,426,765.

The amount of DPPD required to be effective in reducing the toxic effect of tobacco smoke on alveolar (lung) macrophages is from 0.025 to 0.500 grams in a filter for use in cigarettes and pipes, irrespective of the type and size of the cigarette or pipe in present day use. Preferably the amount will be from 0.050 to 0.200 grams.

The percentage of DPPD with carrier material is preferably from 5 70 per cent by weight based on the weight of carrier material, although higher amounts may, of course, be present since the invention is operative with 100 per cent DPPD.

The proportion of glutathione to DPPD may vary widely up to a weight ratio of lO-lor higher, but preferably the glutathione, in order to give increased effectiveness to the DPPD, should be present in a ratio of at least l-l0.

When active carbon is present the weight ration likewise may vary up to a ratio of activated carbon to DPID of l-l or higher, preferably 0.5-l to -1.

Other chemical filtering material may be used in varying amounts, but preferably the DPPD should be present in major amount compared to other material.

The invention is illustrated by reference to the accompanying drawing in which FIG. 1, FIG. 2 and FIG. 3 show views in elevation, partly in section, of cigarettes having different arrangements of filters and different types of chemical filter compositions.

In FIG. I the numeral 10 represents a cigarette consisting of a paper tube 11 packed, except for tip tip portion, with tobacco 16. One end ofthe paper tube 11 (or a separate butt tube) consists ofa section 12 composed of particles of DPPD with or without glutathione between filter sections 13 and 14 composed of cellulose acetate or other known tobacco smoke filter material. The section 12 may also contain DPPD mixed with active charcoal creating a simultaneous mechanical and chemical filter having dual advantages.

In FIG. 2 the numerals l0, l1 and 16 are the same'as in FIG. 1 and the section 12 is composed of a cellulosic filter material impregnated with DPPD, with a plain cellulosic filter 13 at the tip ofthe cigarette. l

In FIG. 3 the numerals l0, l1 and 16 are the same as in FIG. I and the numeral 12 represents cellulosic filter material or other absorbent filter material impregnated with DPPD with or without glutathione. The numeral 15 represents a recess portion of the tip of the cigarette.

Rearrangements of the various combinations shown in the drawings may, of course, be made, and it is not necessary that there be any filter other than the composition consisting of or comprising DPPD.

By having a plain (nonchemical) filter at the tip of the cigarette (FIGSpl and 2) no contact of the smoke with the chemical agent occurs. Likewise, the use ofa recess portion of the tip (FIG. 3) will prevent contact of the smoker with the chemical agent.

The DPPD and DPPD with glutathione additives specifcally employed to reduce the toxic effects of cigarettes on alveolar (lung) macrophages will also restrict certain biochemical changes which occur following exposure of animals and humans to cigarette smoke. These antioxidant filters will contribute to the reduction of chronic pulmonary disease, which can be credited to impaired macrophage function.

The DPPD antioxidant permits to superimposition of a technique which might be described as "selective chemical filtration onto the current commonly used process of mechanical filtration. Having in a general way indicated the nature and purpose of my invention, the following are examples and data by which specific illustrations of the practice of the invention and the advantages to be obtained are demonstrated and are not to be construed as limiting the same.

EXAMPLE 1 Toxic Effects of aqueous Extracts of Cigarette Smoke on Isolated Alveolar Macrophages.

Alveolar macrophages were isolated from rat lungs by the technique oflung washing and equal aliquots ofobtained cells were added to three flasks containing the following:

Flask A. 3 ml ofKrebs-Ringer Phosphate Medium (KRP). Flask B. 2.9 ml of KRP plus 0.1 ml ofKRP smoke solution. Flask C. 2.5 ml of KRP plus 0.5 ml of KRP smoke solution. Flask D. 2.0 ml of KRP plus l.0 ml of KRP smoke solution.

The KRP smoke solution was prepared by bubbling through 10 ml of KRP solution the smoke from one unfiltered cigarette. This solution was used within 10 minutes of its Experiment I Experiment ll Cell Cell Smoke Survival, Survival, Percent Flask Solution 7: 30 Min. 30 Min. 60 Min.

A 0 74.2 69.3 B 0.l mi 72.2 74.5 66.2 C 0.5 ml H9 203 These studies, as well as those to follow, clearly denote the aqueous extracts of cigarette smoke exert a lethal effect on isolated rat alveolar macrophages which is dose dependent. While no reduction in viability was observed when 0.1 ml of smoke solution was added, a 42 and 71 per cent decrease in viability was observed at 30 and 60 minutes, respectively upon the addition of 0.5 ml of smoke solution. When 1.0 ml of smoke solution was added, or a volume equivalent to 0.1 of the original smoke extract obtained from one cigarette, an almost total loss of viability was observed. Thus, exposure of alveolar macrophages to gaseous, water soluble elements of cigarette smoke is associated with significant cellular mortality.

EXAMPLE 2 Further Studies on the the Toxic Effect of Cigarette Smoke.

Additional studies were conducted on the effects of varying concentrations of cigarette smoke on alveolar macrophage viability. Rat alveolar macrophages, 7.5 X 10 macrophages per flask, were incubated in the presence or absence of aqueous extracts of cigarette smoke prepared as Example 1 from one unfiltered cigarette.

These studies confirm the dose dependent toxic effect of aqueous extracts of cigarette smoke on isolated lung macrophages.

EXAMPLE 3 Modification of Toxic Effects of Cigarette Smoke by Antioxidant Filter.

In view of the definitive toxic effects of cigarette smoke extract on isolated alveolar macrophages, attempts were made to modify the toxic effects of smoke extract on alveolar macrophages. .An antioxidant filter was designed and developed (FIG. 1), consisting of 100 mg ofantioxidant filter (50 mg of glutathione and 50 mg of N,N-diphenyl-p-phenylenediamine (DPPD). Control filters were employed using non-antioxidant chemicals, such as sodium chloride (50 mg), and sodium bicarbonate (50 mg), which have comparable physical appearances of the antioxidants. These filters are designated as Inert Chemical Filters, having no antioxidant activity. Aqueous extracts were prepared using the following type cigarettes:

A. Nonfiltered Cigarettes.

B. Antioxidant Filtered Cigarettes.

C. Control lnert or Non-antioxidant Containing Chemical Filtered Cigarettes. D. Regular Commercial Cigarettes.

The aqueous smoke extracts were prepared and added in the amount of 1 ml to incubation flasks containing 1.2 X alveolar macrophage cells isolated from rat lungs. lncubations' were carried out at 37 C for 0, 60 and 120 minutes and cell viability determined at each period by means of the trypan blue exclusion test. The following data were obtained:

Cellulose Acetate Filtered Cell viability, percent Smoke Flask Filter extract 0 min. 60 min. 120 min.

A. 74. 5 6-1. 4 B 17. S 0. O- Antioxidant 71.0 17. (l D Inert chemical- 43.1 1. 8 E. Cellulose acetat 33. 7 4. 5 A... 77.7 611.4 E. 41.7 1. 8 C Antioxidant 80. 2 41. 3 D Inert chemical. 49. 5 0 E Cellulose acetate. 33. 7 0. 97

These studies clearly denote the toxic lethal effects of cigarette smoke extract on cell viability as essentially 100 per cent mortality of alveolar macrophages is observed after 2 hours of incubation (B GROUP). During the initial hour ofincubation, the mean 62 per cent decrease in viability, which characterized the cells incubated in aqueous extracts, was not observed when the antioxidant chemical filter consisting of equal parts of DPPD and glutathione was employed. Significant protective effects are observed at the minute period when the antioxidant filter is employed. Likewise, essentially 100 per cent mortality was seen in the cells incubated with aqueous extracts of cigarette smoke derived from filtered cigarettes, chemical control filtered cigarettes, i.e., the nonantioxidant type filter, and the nonfiltered cigarette.

Thus, the beneficial effect of DPPD antioxidant on negating the toxic effect of cigarette smoke on lungmacrophages is manifested. These macrophages, an important host defense cell of the body, function in phagocytosis and destruction of bacteria, viruses altered or aged cells, as well as the removal and digestion of toxic macromolecular compounds which are present in their environment.

EXAMPLE 4 The influence'of Antioxidant impregnated Filters on Alveolar Macrophage Viability.

The effect of DPPD antioxidant with glutathione impregnated on cellulose acetate filters (FIGS. 2 and 3), in maintaining alveolar macrophage viability was also tested. Our tests indicated that approximately 1 ml of Krebs-Ringer phosphate solution is taken up by a cellulose acetate filter, which were sectioned to enhance surface area. A Krebs- Ringer phosphate medium was prepared, which had a concentration of 50 mg of glutathione and 50 mg of DPPD/per milliliter. The sectioned filters were immersed in the aqueous suspension for one minute, removed and dried under vacuum overnight. The approximate total uptake of antioxidants by each filter was 100 mg. Filters prepared in such a fashion were then inserted back into the end of the cigarette from which the filters were originally removed and aqueous extracts of cigarette smoke prepared from the resulting cigarettes as previously described. Incubation of the aqueous smoke extracts were isolated macropages were conducted at 37 C for 60 and 120 minutes. The results are as follows:

These studies, in essential agreement with previous observations, clearly demonstrate the toxicity of cigarette smoke (group B) and the inability of currently employed filters (group D) to modify the lethal action of cigarette smoke on alveolar macrophages. ln profound contrast, the impregnation of DPPD and glutathione antioxidants into a cellulose acetate filter results in complete inhibition of the lethal effects of cigarette smoke extract (group C).

The protective effect of the DPPD-glutathione filter was due principally to the DPPD, since glutathione did not exert any protective activity on maintaining alveolar macrophage viability in the presence of aqueous smoke extracts. These findings are presented in the following table. As can be observed, the incorporation of glutathione with DPPD resulted filter impregnation.

in enhancement in survival of the smoke exposed pulmonary trapped in 10 milliliters of KRP solution and its macrophages. This suggests a synergistic action between the phosphorescene activity determined prior to, and after, the lipid soluble and water soluble antioxidant on maintaining puladdition of 1 ml of ml peroxide. The hydrogen peroxide was monary macrophage viability. The DPPD filter was found to added to 1 ml of solution prepared from unfiltered cigarette be equally effective if the DPPD was suspended either in water 5 smoke, antioxidant filtered, commercial charcoal filtered, and

to impregnate the filter or dissolved in ethyl alcohol prior to a combination ofcharcoal plus glutathione and DPPD antioxi- 1 dant mixture and counted one minute later by means of a liquid scintillation system. The addition of hydrogen peroxide lNFLUEN E OF DPPD AND GLUTATHIONE ALONE OR results in immediate emission of electromagnetic radiation, or

CONJOINTLY 0N ALVEOLAR MACROPHAGE 10 light, from as yet an unidentified compound present in the VlABlLlTY lN THE PRESENCE OF AQUEOUS SMOKE smoke extract EXTRACT These studies, and those conducted with toluene trapping solutions, indicate that unknown phosphorescent substances are present in cigarette smoke extracts which produce vlabllltyphotons. The excited molecular species, as yet unidentified,

Smoke Incubation Time Filter Extra 0 Min 60 Min product light quanta which can be detected by a phototube of a liquid scintillation counting system. The energy of the excited molecular species is appreciably below that of Triti- 85 um, i.e., less than 0.018 MEV. It can be noted in the table below that the Krebs-Ringer Cellulose Acetate l4 DPRD. 33 Phosphate buffer had background activity (l0-20counts per DPPD" 34 minute). Similarly, in aqueous solutions, like Krebs-Ringer DPPD Glutathio I Phosphate medium, the smoke solutions prepared from the Glumhmne various filters were comparable. However. when hydrogen I peroxide was added to various KRP-smoke solutions, an ap- DPPD s) p p as \valetiuspsnsion imprssnale filtsrproximate twentyfold increase occurred in the photon producxx DPPD 100 mg) dissolved in ethyl alcohol to impregnate filter. i ti it f the am le This contrasted markedly to but a m DPPD and gluwhioneiw s mdmimp'egnae fourfold increase when DPPD plus glutathione was employed in the filter to prepare the KRP smoke solution. Commercial EXAMPLE 5 charcoal-cellulose acetate filter was effective in reducing the increase in photoactivation when compared to the unfiltered cigarette; however, the activity was twice that observed when the chemical antioxidant filter was employed. Employing the activated carbon plus antioxidant filter, prepared as previously described, complete suppression oflight energy from the aqueous solution was obtained.

Evaluation of the Ability ofAntioxidants, Added Directly to the Trapping Solution, to Modify Cellular Toxicity of Cigarette Smoke.

Since antioxidants were protective when incorporated into 35 filters, studies were undertakento determine if the addition of antioxidants directly into the smoke trapping solution would modify the lethal effects of cigarette smoke extracts. To this end, glutat hione and/or DPPD were added in the amount of Counts 100 mg/lO ml of the Krebs-Ringer phosphate trapping'solu- 40 7 per tion and 1 ml of the resulting Smoke extract obtained from un- $38 53 ag filtered cigarettes was added to each flask which contained ap- Flask Filter extract initial cpm. proximately [.2 X 10 alveolar macrophages. None"; 2O 16 B None 14 26B ]C)PPD {{lld glutathione. 15; harcon f L Smok, m minutes E Chnrcoal plus DPPD and 1T 19 Flask In vitro added antioxidant extract 0 1'30 glumthmno' mlxrlmmtli Footnote to above table:

without phosphorous and counted. N0 photoactivity was manifested initially in all samples. When H 0 was added, photoactivation occurred to varying degrees in the aqueous smoke extract solution and was dependent upon filter employed.

Additional studies were conducted where smoke was passed G H DPPD plus glutathtono.

In agreement with our previous observation, aqueous exthrough 20 ml of toluene containing 2.5 diphenyloxazole and tracts of cigarette smoke were toxic to alveolar macrophages -bis-(2-5-phenyloxazolyl)'benzene to enhance detection of (Flask B and E Flask A and p ctively). in contrast to light energy emitted by the sample under study. When samples manifested cytotoxicity, the addition of the water soluble an- 60 were prepared and counted one minute following completion tioxidant, glutathione, and the lipid soluble antioxidant DPPD of preparation, the photoactivity of the toluene sample was into the smoke trapping solution markedly reduced the lethality creased approximately one thousandfold when smoke from an of cigarette smoke (Flasks C and H). Glutathione by itself did unfiltered cigarette was used (sample B vs. sample A). This not appear to exert significant protective effect. was significantly decreased 68 per cent when the DPPD-glu- These studies eliminate the possibility of a non-specific tathionic antioxidant filter was employed. mechanism ofprotection of antioxidants,and indicate that the I I addition of DPPD, or DPPD and glutathione to the KRP medium in vitro, will modify the toxic effects ofcigarette smoke on Activity in alveolar macro ha es. i

p g EXAMPLE 6 70 Sample Filter Smoke Counts/Minute Antioxidants and Photo-activation Studies. In a further effort to evaluate the role of DPPD antioxidant g I I 8 7:2 in reducing alveolar macrophage injury following exposure to C Cellulose Meme cigarette smoke extracts and to evaluate the concept of free D DPPD-Glutathione 15,775

radical generation by cigarette smoke, cigarette smoke was One ml of aqueous extract was placed in scintillation vial EXAMPLE 7 Influence of DPPD Antioxidant Filters on Lipid Soluble Antioxidant Activity of Plasma and Other Tissues of Smoke Exposed Rats.

Studies were also conducted to determine if DPPD antioxidant filters could modify certain specific biochemical events associated with cigarette smoke exposure. Plasma and tissue lipid soluble antioxidant activity was determined in normal, untreated control rats, and in rats exposed to smoke from five unfiltered cigarettes. In addition, groups of rats were also exposed to smoke from five regular filter (cellulose acetate) cigarettes and to smoke derived from five antioxidant filter (FIG. 1) cigarettes. Values below are listed as means standard error of mean and are derived from groups of rats number from 6 to 13.'Values of DPPD lipid antioxidants are expressed as microequivalents of antioxidant per milliliter of plasma or per gram of tissue.

These studies denote that exposure of rats to alternating environments of cigarette smoke and air, by means of a partial vacuum to draw in alternating amounts of air and smoke into an enclosed chamber in which the rats were housed, induces a profound fall in plasma lipid soluble antioxidant activity. The decrease is observed with as little as one cigarette. A regular commercially available cellulose acetate filter does not modify the 72 per cent decrease in plasma lipid antioxidants. However, the decrease observed when the DPPD lipid soluble antioxidant filter was employed was but 44 per cent. In other words, the animals exposed to smoke obtained from DPPD antioxidant filtered cigarettes had plasma antioxidant levels that were approximately per cent higher than that observed when regular filtered or nonfiltered cigarettes were employed. Thus, the depletion of plasma lipid soluble antioxidant activity which follows cigarette smoke exposure is significantly inhibited when DPPD antioxidants are incorporated directly into the cigarette filter.

Thus, by my invention, l have devised a novel filter comprising the lipid soluble antioxidant DPPD which can be readily adapted to reduce the toxicity of cigarette smoke. This chemical antioxidant additive can readily be incorporated by impregnation into conventional type filters or as inserts into conventional filters. The resulting cigarette, which has been smoked by the investigator and others, is a mild, pleasant smoke without appreciable loss of flavor or aroma.

lclaim:

l. A tobacco smoke filter comprising a cylindrical container having a cross-sectional dimension conforming to that of a tobacco smoke passage and defining a space having an inlet and outlet, said space being filled with a smoke permeable composition comprising N,N-diphenyl-p-phenylenediamine in an amount from about 0.025 to 0.500 grams to reduce the toxic effect of tobacco smoke passing through the container on alveolar macrophages, the amount used not being toxic to the smoker.

2. A tobacco smoke filter according to claim 1 in which the N,N-diphenylp-phenylenediamine is mixed with glutathione.

3. A tobacco smoke filter according to claim 1 wherein the N,N'-diphenyl-p-phenylenediamine is impregnated into a cellulosic smoke filtering material.

4. A tobacco smoke filter according to claim I wherein the N,N-diphenyl-p-phenylenediaminc is incorporated with activated charcoal.

5. A tobacco smoke filter according to claim 2 wherein the mixture is impregnated into a cellulose acetate filtering material.

6. A tobacco smoke filter adapted to remove undesirable components from tobacco smoke, said filter having a crosssectional dimension conforming to that of a tobacco smoke passage and comprising a carrier material and an amount of from 5 per cent to 70 per cent by weight based on the weight of said carrier of N,N'-diphenyl-p-phenylenediamine to reduce the toxic effect of tobacco smoke passing through said passage, the amount used not being toxic to the smoker. 

2. A tobacco smoke filter according to claim 1 in which the N, N''-diphenyl-p-phenylenediamine is mixed with glutathione.
 3. A tobacco smoke filter according to claim 1 wherein the N,N''-diphenyl-p-phenylenediamine is impregnated into a cellulosic smoke filtering material.
 4. A tobacco smoke filter according to claim 1 wherein the N,N''-diphenyl-p-phenylenediamine is incorporated with activated charcoal.
 5. A tobacco smoke filter according to claim 2 wherein the mixture is impregnated into a cellulose acetate filtering material.
 6. A tobacco smoke filter adapted to remove undesirable components from tobacco smoke, said filter having a cross-sectional dimension conforming to that of a tobacco smoke passage and comprising a carrier material and an amount of from 5 per cent to 70 per cent by weight based on the weight of said carrier of N,N''-diphenyl-p-phenylenediamine to reduce the toxic effect of tobacco smoke passing through said passage, the amount used not being toxic to the smoker. 